An insertion finger of the afore-described type is described in German Gebrauchsmuster No. G 85 21 173.7 As are other conventional integrally formed insertion fingers, it is suitable only for the insertion of coils into stators exhibiting straight-lined axially parallel grooves.
Twisted stators (the grooves of which are helically formed throughout the axial length thereof), in a multiplicity of end-use applications, exhibit better electrical properties than stators comprising axially parallel grooves. However, hitherto, the coils had to be manually placed into the helical grooves. Alternatively flexible tongues respectively connected in pairs and also guided in pairs in a single stator groove of the type as described in DE-PS No. 26.58.891 had been used for this purpose. Admittedly, the flexibiltiy of these tongues permits its resilient deformation conforming to a helical stator groove,
However, the flexibility thereof is the cause for the substantial disadvantages of such tongues. Through the coils accommodated therein, they are non-uniformly deformed and bulged, respectively, throughout the length thereof, this resulted, through heavy friction on the sharpedged stator sheets in the area of the bulging and on the ends springing apart, in extremely rapid wear. Moreover, the flexible tongues entangle in the helical stator grooves, thus being likely to lose the desired guidance of and abutment with the edges of the stator teeth.